The investigations proposed herein are designed to elucidate basic aspects of the immunobiology of monocytes and macrophages in human ovarian tumors. Mononuclear phagocytes will be isolated from the peripheral blood and ascitic tumors of patients with epithelial ovarian neoplasms and their cytolytic activity will be measured using in vitro tumor cell lines. Cytotoxicity of mononuclear phagocytes will be compared to that of peripheral blood monocytes and peritoneal macrophages of age-matched patients with non malignant diseases. Attempts will also be made to isolate and test macrophages from primary solid ovarian tumors. In parallel experiments, primary ovarian carcinoma cultures from peritoneal effusions and solid tumors will be analyzed for their susceptibility to macrophage cytotoxicity (lysis and/or stasis). We will also investigate whether stimuli, such as endotoxin and lymphokines, effective in experimental murine systems, can enhance the cytocidal capacity of mononuclear phagocytes of ovarian carcinoma patients or control subjects. It is expected that the present study will provide experimental evidence relevant to a better understanding of the role of mononuclear phagocytes in the control of human neoplasia.